微視的な不均質構造によって生じる巨視的な不均一変形のモデル化に関する研究

抄録

Engineering materials typically have a heterogeneous microstructure, and it induces microscopic non-uniform deformation even under the macroscopically uniform stress state. With the decrease in the dimension of engineering structural components, such a microscopic non-uniform deformation affects the macroscopic deformation state. In this study, the development of the microscopic heterogeneity-induced non-uniform deformation is modeled using the rate-form nonlocal constitutive equation. First, the inelastic strain is decomposed into local and nonlocal inelastic strains. Then, the nonlocal strain is assumed to be developed by the distribution of plastic compliance, which is characterized by an intrinsic size of the material microstructure. Finally, the multiaxial rate-form constitutive equation, in which the stress on the material points is calculated by both the local and nonlocal strains, is formulated. The finite element simulations of the tensile tests of specimens with curved and parallel gauge sections are performed using the proposed model. The obtained results clarified that the mechanical response and the non-uniform deformation are characterized by the microscopic heterogeneity of the material.